Optical recording medium having unrecordable restricted block(s), and systems incorporating same

ABSTRACT

In a medium having a restriction on its function, which has a extremely low overwrite cyclability as compared with a common one, information is arranged so as to allow restricted write and read operations in a commonly used current write and read drive, i.e., the medium is subjected to specific formatting. It is possible to perform write and read operations with security. The specific format can be performed with parameters taking into consideration special-purpose use conditions (i.e., overwrite cyclability). Consequently, it becomes possible to provide a low-priced information recording medium.

BACKGROUND OF THE INVENTION

The present invention relates to the arrangement of recorded data on aninformation recording medium. More particularly, it relates to aninformation recording medium including information arranged thereon soas to allow restricted writing and reading in a commonly current writeand read drive, and a system for performing restricted write and readoperations on and from the information recording medium.

One example of a conventional optical recording system will be describedwith reference to FIGS. 3 and 5 as one example of an informationrecording system.

FIG. 3 shows a block diagram of a conventional optical write and readdrive. The light beams emitted from a laser 25 (with a wavelength ofabout 660 nm for a DVD-RAM), which is a part of a head 2, are collimatedinto a nearly parallel light beam 22 through a collimating lens 24. Thelight beam 22 is applied onto an optical disk 11 through an objectivelens 23 so as to form a spot 21. Thereafter, the reflected light beamsare guided through a beam splitter 28, a hologram element 29, or thelike, to a servo detector 26 or a signal detector 27. A signal from eachdetector is subjected to an add/subtraction process to become a servosignal, such as a tracking error signal or a focus error signal, whichis then inputted to a servo circuit. The servo circuit controls thepositions of a driving means 31 of the objective lens 23 and the wholeoptical head 2 based on the tracking error signal and focus error signalthat has been obtained, so that the optical spot 21 is positioned in anobjective writing and reading area. An added signal from the detector 27is inputted to a signal reproduction block 41. In a signal processingcircuit, the inputted signal is subjected to a filtering process and afrequency equalizing process, and then is subjected to a digitizationprocess. The digital signal thus subjected to a digitization process isprocessed by an address detector and a demodulation circuit. Based onthe address signal detected by the address detector, a microprocessorcalculates the position of the optical spot 21 on the optical disk 11and controls a position control means, thereby to position the opticalhead 2 and the optical spot 21 at an objective recording unit area(sector).

If the instruction from a host to the optical write and read drive is awriting instruction, the microprocessor receives recording data from thehost and stores it in a memory, while controlling the position controlmeans to position the optical spot 21 at a position in an objectiverecording area. The microprocessor checks that the optical spot 21 hasbeen properly positioned in the recording area by an address signal fromthe signal reproduction block 41, and then controls a laser driver andthe like to write the data in the memory on an objective recording area.

An address signal is arranged in every information recording unit area,at the beginning portion of the recording unit area, as shown in FIG. 6.Therefore, it is possible to check the position of the optical spotimmediately before writing by detection of the address signal.

FIG. 5 shows an example of the flow of operation of an optical recordingsystem for driving the DVD-RAM disk specified in International StandardISO/IEC-16824, or the like, which is a rewritable DVD or DVD-RAMrepresenting one example of the optical recording system describedabove.

When a disk is loaded, or the power of the optical recording system isturned on, first, the optical recording system performs a process fordiscriminating the types of media. In general, it has a function ofreading a CD-ROM or DVD-ROM which is a read-only medium, in addition tothe DVD-RAM medium. Therefore, the optical recording system firstperforms a media type discrimination process to discriminate which oneof the types described above the medium corresponds to. Individualsystems perform the discrimination process in mutually different ways.For example, some systems discriminate the types of media from theanalogue characteristics of the reflectance and the reproduced signal,such as the focus error signal, and other systems read a physicalinformation area provided on a disk substrate and then discriminate thetypes of media based on the contents (data).

If the optical recording system identifies the type of the medium as arewritable type, i.e., a DVD-RAM, first, it checks the recorded contentsof a defect management information area, and the like, and therebychecks whether the optical disk has been physically formatted. If theoptical disk has not been physically formatted, a wait period isinitiated until a physical format command is issued from a host or auser.

If the optical disk has been physically formatted, the optical recordingsystem performs a process of preparation for writing, such as acalibration process or logical consistency verification, and then itenters a wait state for a command from a user or host. Upon receivingsome command, the optical recording system checks the type of thecommand. Then, if it is a write command, the optical recording systemperforms a writing process. For commands of read, format, unloading ofthe disk, and the like; the optical recording system performs respectivecorresponding processes. In general, these processes are normallyterminated. However, in case of an unsuccessful write operation for anunexpected reason, the system performs an error handling process, suchas retry or replacement.

In general, with a DVD-RAM, during the writing process, whether therecording data has been normally written or not is checked by actuallyreading the recorded data. If required, replacement is performed byusing another recording unit area, thereby to enhance the reliability ofthe recorded data. The management information on the reallocation ofrecording areas due to the replacement is written in a specific area(defect management area).

Thus, the DVD-RAM is an optical recording system having very highreliability. However, since the recorded data is basically freelyrewritable, it is not possible to eliminate the possibility that theimportant data already recorded is erased or rewritten due to a wrongoperation by a user, a malfunction of the host, or the like.

Further, replacement is performed on the following precondition: even ifrewriting processes are performed for a sufficiently larger number oftimes than the number of defects storable in the defect management area,it is possible to perform writing and reading with no problem.

As one method of protection, there is a so-called write protectionfunction. However, the write protection can be freely revoked by a user.Accordingly, it is still impossible to prevent data corruption by thewrong operation of a user.

An example of a magneto-optical disk will be described as a proposal forovercoming such a problem. The magneto-optical disk is a rewritablestorage medium that is capable of erasing and rewriting user data withrespect to a user data area including user data recorded therein.However, there is a demand for this to be used as a WORM type storagemedium not capable of erasing and rewriting user data.

For example, with a CCW method specified in International StandardISO-1EC11560 (or a MO-WORM method), media type identification dataindicative of the type of the magneto-optical disk is included in acontrol information area provided in an area outside the user data areaof the magneto-optic disk. As a result, it is possible to identifywhether the magneto-optical disk is of a rewritable type or a WORM typebased on the media type information.

The magneto-optical disk drive is so configured that, if the WORM typemagneto-optical disk is loaded therein, the erasing operation and therewriting operation are not to be performed with respect to the userdata area including user data already written therein. Namely, themagneto-optical disk, which is originally of a rewritable type, isprovided with a write protection function for preventing erasing andoverwriting. Consequently, it becomes possible to access a WORM typemagneto-optical disk having a write protection function and a rewritablemagneto-optical disk with the same magneto-optical disk drive.Accordingly, the magneto-optical disk drive finds a wider range ofapplication, and it is also possible to reduce the media cost.

However, if an attempt is made to apply the same method to an opticaldisk system with only a rewritable type standard already set therein,such as a DVD-RAM, the following problem occurs.

The standard of the rewritable disk already exists, and such a disk iscommercially available. An optical disk system for driving an opticaldisk in conformity with the standard also already exists. Even if mediatype data of the media type identification data area is newly defined,as in the example of the magneto-optical disk under such circumstances,it is not possible to change the existing drive. Therefore, it isimpossible to control the operation of the existing optical disk drivehaving no write protection function.

Actually, as described above, all optical recording systems do notutilize media type identification data for discriminating the mediatypes. Further, even if novel encoded data which has been undefined inthe art is written to the media type identification data, the operationhas been undefined because a conventional optical recording systemcannot recognize the meaning of the encoded data.

Namely, in the prior-art example, there has been a risk that the data onthe optical recording medium is corrupted by a mistake with the existingrecording drive when a medium with a restriction on its function, suchas a low-priced medium providing low overwrite cyclability isintroduced.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a secure opticalrecording system which imposes a restriction on its method of use, forexample, imposes a substantial restriction on the rewrite count of amedium without changing the hardware or physical specifications, andeliminates a risk that recorded information is corrupted or recordedinformation is lost as with a conventional drive even for a medium withlow overwrite cyclability or a low-priced medium.

The following features were Used in order to attain the object of thepresent invention.

(1) Out of user recording blocks of the information recording medium, atleast one or more blocks have been set to be unrecordable, unreadable,or inaccessible restricted blocks. The term “restricted” as herein useddenotes that a restriction is imposed on the rewrite count of a specificarea, such as a defect management area.

Consequently, it is possible to disable the substantial use thereof in asystem which does not recognize the presence of the restricted block.Accordingly, it becomes possible to force the use of specific controlsoftware or a specific logical format, thereby making it possible torestrict the method of use of the disk. For example, it becomes possibleto prohibit the use of a disk shipped with a specific logical format byreformatting the disk in another format, or the like. By utilizing thisfact, it becomes possible to use a medium with a restriction on itsoverwrite cyclability with security, as will be described later.

(2) The user recording block has been set to be an error correction code(ECC) block composed of a plurality of user sectors. Consequently, itbecomes easy to apply the present invention to a system which recordsdata in a unit of the ECC blocks (such as a DVD-RAM). The ECC block,which is the unit for recording, is not necessarily required to be inagreement with a sector, which is the minimum unit of the addressableblock as seen from the host system. For example, in a DVD system,2048-byte user data can be stored in one sector, and the ECC block iscomposed of 16 sectors, i.e., data of about 32 kB.

(3) The user sectors individually have independent address numbers, andall the user recording blocks to which the user sectors belong, whichhave the smallest 257, or more desirably 513, address numbers out of theuser sectors, have been set to be at least unrecordable, unreadable, orinaccessible restricted blocks. Alternatively, all the user recordingblocks to which the user sectors belong, which have the largest 257address numbers out of the user sectors, have been set to be at leastunrecordable, unreadable, or inaccessible restricted blocks. Namely, thelowermost 257 blocks or 513 blocks, and/or the uppermost 257 blocks, inthe user address space have been at least substantially set to bedisabled.

Consequently, it is possible to substantially make it impossible toformat or reformat a recording medium for use by ordinary logicalformatting software whereby a file system area is arranged at thebeginning portion of the user area. Therefore, it is possible tosubstantially restrict the use of the format using other formattingsoftware than the objective software of the present invention. Thus, itis possible to restrict the method of disk use with reliability.Particularly, it is possible to restrict the ordinary formatting withreliability in a UDF file system using sectors 256 and 512 as referencesectors (AVDPs: Anchor Volume Descriptor Pointers). Since some filesystems allocates system information to the end portion of the volumespace (data area), it is more desirable for the disabled area to be alsoallocated to the end portion.

(4) An information recording medium is used, which comprises: at least aplurality of independently writable and readable user recording blocks;and spare blocks each for replacing a user recording block having adefect, wherein at least one or more blocks out of the spare blocks havebeen set to be an unrecordable, unreadable, or inaccessible restrictedblocks.

Consequently, it becomes possible to apply the write restriction methodeven to a system having a replacement function (ex., DVD-RAM) withreliability.

For achieving the foregoing object, it is desirable to use aninformation recording medium, which comprises: at least a plurality ofindependently writable and readable user recording blocks, and three ormore blocks of spare blocks, each for replacing a user recording blockhaving a defect, wherein at least three or more consecutive blocks outof the spare blocks are unrecordable, unreadable, or inaccessiblerestricted blocks. In a conventional DVD-RAM system, when a defectexists in the block itself to be used as a spare block, its adjacentrecording blocks are automatically reallocated as spare blocks. However,if three or more consecutive blocks are disabled, as described above, itbecomes impossible to normally perform the reallocation function.Consequently, it is possible to impose a restriction on the use withhigher reliability.

(5) As a means for implementing the unrecordable, unreadable, orinaccessible restricted blocks a medium is used in which address numbersare arranged as the physical address data, each made up of at least acode indicative of an address number and an address error detection codefor verifying the correctness of the address number, and some of theaddress numbers are at least included, in each of which there is amismatch between the codeword indicative of an address number and theerror detection code for verifying the correctness of the addressnumber. Consequently, with a conventional drive, address detection isdisabled, so that the corresponding portion becomes unrecordable,unreadable, or inaccessible. Since some systems ignore a little addresserror, it is recommendable that a plurality of, and more desirably threeor more blocks, each with address mismatch, are included in the blocksin order to impose a restriction on writing with higher reliability.

(6) The address number is arranged as the physical address data made upof at least a code indicative of an address number and an address errordetection code for verifying the correctness of the address number onthe recording medium. As for the physical address data corresponding tothe unrecordable, unreadable, or inaccessible restricted blocks out ofthe physical address data, each address number indicated by the physicaladdress data has been set to be different from the address number of theblock. Consequently, it becomes impossible to gain the objective addresswith a conventional drive, so that the corresponding portion becomesunrecordable, unreadable, or inaccessible.

(7) An information recording medium is used which comprises at least twoor more independently writable and readable user recording blocks,wherein out of the user recording blocks, at least one or more blocksare unrecordable, unreadable, or inaccessible restricted blocks.Further, a map or list of information indicative of the existingpositions or addresses of all the restricted blocks are prerecorded asencoded data or encrypted data on a specific area or desirably on aread-only area where information is recorded by embossed pits or thelike on the information recording medium.

Consequently, only a processing system capable of decoding the specificauthorized cipher can use the recording medium of the present invention.Therefore, it becomes possible to ensure security.

(8) The recording medium is to be previously logically formatted so thatan area, except for that of the unrecordable, unreadable, orinaccessible restricted blocks, is a substantial user area prior toshipment.

Consequently, it becomes possible to perform writing and reading on themedium of the present invention without any specific software in aconventional system. Even in such a case, the medium substantiallybecomes unusable if it is formatted in another system, and hence it ispossible to substantially restrict the method of use so as to bedifferent from the intended method of use of an information recordingmedium provider. Therefore, it becomes possible that the recordingmedium manufacturer assumes the restricted use method of the medium.Consequently, the flexibility of the specifications is increased, sothat it becomes possible to provide a substantially low-priced recordingmedium.

(9) The write restriction as described above has been implemented byconfiguring a system such that an information recording medium having awrite and read restriction comprising at least two or more independentlywritable and readable user recording blocks, out of the user recordingblocks, at least one or more blocks being unrecordable, unreadable, orinaccessible restricted blocks, is used in a computer system or a writeand read drive having a processing function for performing read andwrite control, such that an area except for the restricted blocks, is asubstantial user area.

This system is so configured that, for example, a standard read andwrite drive is connected to a host onto which specific control softwarehas been installed.

(10) An information recording and reproducing system having a write andread restriction has been configured which comprises: an informationrecording medium having a write and read restriction comprising at leasttwo or more independently writable and readable user recording blocks,out of the user recording blocks, at least one or more blocks beingunrecordable, unreadable, or inaccessible restricted blocks; and a meanshaving a processing function for reading encoded data or encrypted datastored in a specific area on the recording medium, and decoding ordecrypting the read data to obtain layout information of the restrictedblocks, and performing at least one of write and read control or logicalformat, such that all the restricted blocks are not substantially userareas based on the restricted block layout information obtained by usingthe information recording medium.

Consequently, it becomes easy to add high security to the specificationrestriction. Accordingly, it becomes easy to restrict the use by anunauthorized user, or to restrict the use of software.

(11) An information recording and reproducing system has been configuredwhereby the restricted blocks are substantially excluded from the userarea by registering the restricted blocks as defects, or the restrictedblocks are substantially excluded from the user area by registering therestricted blocks as invisible files.

This enables the use of a restricted disk.

(12) An information recording medium is used which comprises: at least aplurality of independently writable and readable user recording blocks;and spare blocks each for replacing a user recording block having adefect, wherein the number of the spare blocks has been set to besmaller than the overwrite cyclability of the recording medium.

For example, in a 120-mm-dia DVD-RAM (4.7 GB per side), a PSA (primaryspare area) and an SSA (supplementary spare area) can be ensured asspare blocks. Out of these areas, only the PSA is assigned at the timeof shipment, and further, a part of the area is previously registered asused blocks. Consequently, the number of newly usable spare blocks isset to be smaller than the overwrite cyclability determined by thephysical characteristics of the recording layer of the medium.

As a result, the write and read drive performs replacement registrationwhen a defect is newly found during use of the medium, and every timethe replacement registration process is performed, the defect managementarea, which is a specific area of the medium, is rewritten once. Byusing this technique, it is possible to restrict the number of cyclesfor rewriting the defect management area associated with the replacementto not more than the number of usable spare blocks, i.e., the rewritecount of the medium. This eliminates the danger that the rewrite countof the defect management area exceeds the overwrite cyclability.Consequently, the reliability of the medium is improved.

(13) An information recording medium is used, which comprises: at leasta plurality of independently writable and readable user recordingblocks; spare blocks each for replacing a user recording block having adefect; and at least a defect management table recording area forrecording the relationship between the defective blocks and the spareblocks, wherein a plurality of the defective blocks and the spare blockshave been previously recorded in the defect management table, and thenumber of residual blocks registrable in the defect management table hasbeen set to be smaller than the overwrite cyclability of the recordingmedium.

For example, in a 120-mm-dia DVD-RAM (4.7 GB per side), the defectmanagement tables are of two types: a PDL (primary defect list) tableand a SDL (secondary defect list) table. Out of these, in the PDL table,about 7000 sectors of defects can be registered, and about 4000 blocksof defects can be registered in the SDL table. In this way, most of theentries of the SDL table are assigned by replacement registration.Further, a part of them are previously registered as having been used tobe the used blocks. Consequently, the number of defective blocks usableby additional assignment is set to be smaller than the overwritecyclability determined by the physical characteristics of the recordinglayer of the medium.

As a result, the write and read drive performs defect registration whena defect is newly found during use of the medium, and every time thereplacement registration process is performed, the defect managementarea, which is a specific area of the medium, is rewritten once. Byusing this technique, it is possible to restrict the number of cyclesfor rewriting the defect management area associated with the defectmanagement to not more than the number of usable spare blocks, i.e., theoverwrite cyclability of the recording medium. This eliminates thedanger that the rewrite count of the defect management area exceeds theoverwrite cyclability. Consequently, the reliability of the medium isimproved. Herein, the defect registration denotes that a defect isregistered as a defect, and it is not necessarily identical with thereplacement assignment.

Any of the replacement assignment in the foregoing section (12) and thedefect registration in the foregoing section (13) results in rewritingof the defect management area. Therefore, it is desirable that the sumof both the number of the spare blocks and the number of residual blocksregistrable as defects is set to be smaller than the overwritecyclability of the recording medium.

Further, at worst, there can be present the case where the replacementassignment described in the foregoing section (12) is performed afterthe defect assignment described in the foregoing section (13), and then,after spending the spare blocks, defect registration is performed withno replacement as in the means (13). Any of the steps results inrewriting of the defect management area. Therefore, it is more desirablethat the number of the spare blocks and the number of the residualblocks registrable as defects are set to be smaller than one third ofthe overwrite cyclability of the recording medium, respectively.

(14) The total number of the restricted blocks on the informationrecording medium has been set to be larger than the total number of therecording blocks registrable in the defect management table.Consequently, even if an attempt is made to perform reformatting withcertification, all the u˜xrecordable blocks (restricted blocks) cannotbe registered as defects. Accordingly, reformatting is unsuccessfullyterminated. Namely, it is possible to disable (restrict) reformatting.

Other and further objects, features and advantages of the invention willappear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred form of the present invention is illustrated in theaccompanying drawings, in which:

FIG. 1 is a diagram illustrating the object and the effect of thepresent invention;

FIG. 2 is a block diagram showing one example of an optical write andread drive;

FIG. 3 is a block diagram showing another example of an optical writeand read drive;

FIG. 4 is a diagram showing an example of the logical format of aninformation recording medium of the present invention;

FIG. 5 is a flowchart illustrating the operation with the optical writeand read drive;

FIG. 6 is a diagram showing the manner in which address information isarranged;

FIG. 7 is a flowchart illustrating the operation of the presentinvention;

FIG. 8 is a diagram showing another manner in which address informationis arranged;

FIG. 9 is a diagram showing an example of the information recordingmedium of the present invention, which has been logically formatted witha conventional device;

FIG. 10 is a diagram showing an example of the logical format of theinformation recording medium of the present invention; and

FIGS. 11(a) and 11(b) are diagrams respectively showing theconfigurations of defect management lists.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLE 1

FIG. 3 shows a block diagram of one example of a DVD-RAM write and readdrive which is a conventional optical information recording drive.First, the operation in the case where a conventional medium with nowrite restriction is loaded in this drive will be described. The lightbeams emitted from a laser 25 (with a wavelength of about 660 nm for aDVD-RAM), which is a part of a head 2, are collimated into a nearlyparallel light beam 22 through a collimating lens 24. The light beam 22is applied onto an optical disk 11 through an objective lens 23 to forma spot 21. Thereafter, the reflected light beams are guided through abeam splitter 28, a hologram element 29, or the like, to a servodetector 26 or a signal detector 27.

A signal from each detector is subjected to an add/subtraction processto become a servo signal such as a tracking error signal or a focuserror signal, which is then inputted in a servo circuit. The servocircuit controls the positions of the objective lens 23 and the wholeoptical head 2 based on the tracking error signal and focus error signalthus obtained, so that the optical spot 21 is positioned in an objectivewriting and reading area. An added signal from the detector 27 isinputted to a signal reproduction block 41. By a signal processingcircuit, the inputted signal is subjected to a filtering process and afrequency equalizing process, and then to a digitization process.

The digital signal thus subjected to a digitization process is processedby an address detector and a demodulation circuit. A physical sectornumber (PSN), which is physical address information, is obtained by theaddress detector. The address information herein obtained corresponds tothe recording sector of the medium. In a DVD-RAM system, the PSN at thebeginning of the user data area starts from “31000h”. However, in suchan external recording drive to be connected to a host, such as a PC, asthe drive of the present invention, if the start address of therecording area varies from one type to another type of drive, theprocess at the host becomes complicated. Therefore, an access isgenerally made from the host by using a logical block address (LBA). Inthe drive of this example, the translation between LBA and PSN iscarried out in a microprocessor in the drive. However, an addressconverter may also be used, as provided in the example of FIG. 2.

The microprocessor discriminates the types of medium loaded therein (seeFIG. 4), and if the medium is a DVD-RAM, the microprocessor reads thedefect management table (PDL and SDL) stored in defect management areas(DMA) on the outer sides (respective two portions of the innercircumference side and the outer circumference side) of the data area,and performs skipping or replacement of the defective sector toestablish a correspondence between PSN and LBA. In a DVD-RAM disk with adiameter of 120 mm and a capacity of 4.7 GB per side, the user data areais positioned at from PSN=31000h on the innermost circumference side toPSN=265F5Fh on the outermost circumference side. Within the area, thearea at from 31000h to 341FFh is ensured as a primary spare area (PSA)for replacement of defective sectors. The PSA includes 12800 (3200h)spare sectors. In a DVD-RAM, it is possible to ensure a supplementaryspare area (SSA) at the outermost circumference in addition to the PSA.In this example, the SSA of 49152 sectors at from PSN=259F60 toPSN=265F5F is ensured at the outermost circumference. As a result, theuser data area actually specifiable ranges from PSN=34200h toPSN=259F5Fh. Within this range, 2252128 sectors are included. However,the DVD-RAM disk is configured in accordance with the zone CLV scheme.Therefore, 2245920 sectors, except for guard areas of the zone boundaryportions, serve as user sectors. Accordingly, the user sectors are incorrespondence with LBAs of LBA=0 (PSN=34200h) to LBA=2245919(PSN=259F5Fh).

The defect management tables are of two types: a PDL (primary defectlist) and a SDL (secondary defect list) (FIGS. 11(a) and 11(b)). Ingeneral, the PDL is used for registering the initial defects found atshipment of the medium or at certification. The PSN of each defectivesector is recorded in the PDL, so that the read and write drive does notassign an LBA to the sector having the PSN listed in the PDL (Slipping).The read and write drive assigns LBAs thereto so that the user data areaencroaches into the PSA by the area corresponding to the sectorssubjected to such Slipping. To be precise, the beginning portion of theuser data area undergoes a little surplus shift in excess of the areacorresponding to the number of entries registered in the PDL into thePSA. This is attributable to the following fact: the DVD-RAM is radiallydivided into a plurality of recording zones, and if fractional sectorswhich fall short of the defect management block (16 sectors) are left atthe boundary portion of the zone, the portion cannot be specified.Namely, the beginning of the user data area shifts in the direction inwhich the PSN is smaller than PSN=34200h (toward the innercircumference).

In the PDL, 7679 items of defect sector information can be registered ata maximum. The read and write drive registers the defects found duringuse in the SDL and assigns their respective spare blocks thereto. Inthis step, replacement is performed in a unit of the error correctioncode made up of 16 sectors. The SDL lists the one-to-one correspondencebetween the PSN of the top sector of each defective block and theaddress of the top sector of its corresponding replacement address. TheSDL can register the defective information of 3837 blocks. The write andread drive successively registers the defects found during use in theSDL. Therefore, the SDL is to be rewritten about 4000 timescorresponding to the number of registrable entries.

In general, the DVD-RP˜N can be rewritten about 100000 times, and henceabout 4000 occurrences of rewriting do not matter at all. However, for aphase-change type recording medium, such as a DVD-RAM, delicateadjustment of the laminate structure for suppressing the material flowof recording layer materials, or a specific layer for inhibiting themixing of the recording layer and protective layer materials becomesnecessary in order to perform rewriting a large number of times.Accordingly, delicate adjustment of the composition of the mediumrecording layer or the laminated structure becomes absolutely necessary,causing an increase in media production cost. Namely, the media price isincreased.

Conversely, if the rewrite count is restricted to several hundred toseveral thousand, the delicate adjustment of the composition of themedium recording layer or the laminated structure becomes unnecessary.Accordingly, the laminated structure is simplified, or the mediaproduction margin is expanded. As a result, it becomes possible toprovide a very low-priced medium.

Therefore, in this example, it is assumed that a medium with anoverwrite cyclability of from about several hundred times to thousandtimes is used as a low-cost medium.

For example, for an overwrite cyclability of 1000 times, if a part ofthe user data area is frequently rewritten (actually, there is an areawhich is frequently rewritten even in the case of ordinary use in a partof a file system), the recording layer characteristics in the area aredeteriorated, resulting in a read or write error. However, the DVD-RAMhas a defect management function. Therefore, such a defective area ishandled as a defect, and hence an undeteriorated spare Sector (spareblock) is assigned thereto. Since such assignment can be performed forevery deterioration, the overwrite cyclability effective from theviewpoint of a user can be ensured to be one hundred thousand times ormore. However, reassignment of the spare area is repeatedly performed,and rewriting of the SDL is required for each reassignment step.Therefore, the SDL itself may be deteriorated. In a DVD-RAM, replacementof the SDL itself is not performed. Accordingly, the SDL information islost at the worst, so that the information of the whole recording mediummay become inaccessible. Thus, in this example, the following recordingmedium was used so that a medium having a restriction on its overwriteavailability may be used in a conventional system with no problem (seeFIG. 4):

(1) A total of 12800 sectors of the 4096 sectors (PSN=34200h−PSN=351FFh)at the beginning portion of the user data area and the 8704 sectors(PSN=32000h−PSN=34200h) to be used at first within the PSA have been setto be an unrecordable area.

(2) The 4096 blocks (65536 sectors) at PSN=255F60h to PSN=265F5Fh at therearmost portion of the user area have been set to be an unrecordablearea.

(3) The unrecordable area has been implemented by setting the ID errordetection data (IED) (see FIG. 8) of the ID which is the address data soas to indicate mismatch.

(4) The SSA has not been assigned. Therefore, the rearmost portion ofthe user data area is located at a position where PSN=265F5Fh. (Totalnumber of user sectors is 2295072.)

(5) A total of 7679 sectors of the known defective sectors other thanthose described in the foregoing items (1) and (2) and a part of theunrecordable sectors of (1) have been previously registered as P-List inthe PDL. Therefore, the beginning portion of the user area shifts fromthe position where PSN=34200h to the side on which the PSN is reduced byabout 7670 sectors. Namely, the physical user area top sector (LBA=0) islocated in the vicinity of a position where PSN=32400h.

(6) Within the area described in the foregoing item (2), 3734 blocks(except for the recording block corresponding to the position whereLBA=2294815) have been previously registered in the SDL. However, uponregistration, an SLR flag was set to 1 bit, and no spare sector has beenassigned thereto.

(7) The recording block corresponding to LBA=256, LBA=512, and LBA=finalLBA−256=2294815 have been previously registered in the SDL, and assignedspares. In this step, the portion extending from the position wherePSN=31640h to the position where PSN=3167Fh was utilized forreplacement.

(8) Logical formatting was previously performed with a UDF file system.In this step, the 12288 sectors (3000h) at the beginning of the userdata area and the 65536 sectors (1000h) at the rearmost thereof were notused.

(9) The overwrite cyclability of the medium (recording layer) was set tobe not less than 300 times.

Below, the principle of operation of this example will be described. Inthis example, an unrecordable area is present. However, since theunrecordable area is not present in a logical user area (logical volumespace), which is the user recording area after logical formatting, thereis no problem for common use. For the UDF format, the layout positionsof only a Volume Recognition Sequence (VRS) and an AVDP (Anchor VolumeDescriptor Pointer) are determined, and the VRS is to be recorded atLBA=16, and the AVDP5 are to be recorded at two or more positions out ofthe positions where LEA=256, LBA=512, and LBA=N−256 (where N is thefinal LBA). For the 4.7 GB DVD-RAM, to which this example relates, theAVDP5 are recorded at the two positions where LBA=256 and LBA=2294815.In the AVDP, the layout positions of two main and spare volumedescriptor sequences (VDSs) are recorded. In this example, the VDSs havebeen located at 16 sectors beginning at LBA=12288, and 16 sectorsbeginning at LBA=12288+16. At the subsequent sectors, an LVID (logicalvolume integrity descriptor) has been located, and the logical volumespace has been located so as to begin at LEA=12288+256, and end atLBA=2229279 (=2295072−65536−1). Namely, the number of sectors whichbelong to the logical user area after logical formatting is 2216992, andthe capacity thereof (logical volume space) is about 4.54 GB. In thelogical volume space, a space bit map, a file set descriptor, adirectory, a user file, and the like are located.

In this example, the sectors where LBA=256 and LBA=2294815 fordescribing the AVDPs, and the sector where LEA=16 for the VDS arebasically located in the unrecordable area. However, the LBAs havepreviously been assigned for replacement to the area outside theunrecordable area in the PSA. Therefore, actually, they are recorded inthe assigned replacement recording block (at from PSN=31640h toPSN=3167Fh). Other file system data are all assigned to the area whichis not unrecordable in the user area.

If another defective sector occurs due to deterioration caused byrewriting, adhesion of contaminants, or the like during use of themedium, the sectors at from PSN=3163Fh to PSN=31000h are successivelyassigned as replacement areas. In this example, the sectors at PSN=3164Oh to PSN=3167Fh have previously been assigned and registered asreplacement sectors. Therefore, the area between PSN=31680h andPSN=341FFh in the PSA is regarded as a used spare area, and hence theyare not to be assigned as replacement sectors. For this reason, thedefect management can be performed with respect to a newly occurreddefect with no problem. In this example, only the 100 blocks (64 Oh) atPSN=3163F to 31000h are used as a spare area. The spare area is presentonly for 100 blocks. Therefore, the number of cycles for performingreplacement assignment is 100 at maximum. Namely, the SDL rewrite countis also restricted to 100.

In the DVD-RAM, there is provided a function of performing onlyregistration of a defect, but not performing a replacement assignment,other than the replacement assignment. In this case, the defect is to beregistered in the SDL in the same manner as with the replacement.However, the replacement assignment is not performed, and the flag SLRis set to “1”, thereby indicating that the replacement assignment hasnot been performed (see FIG. 11(b)). Even in this case, the defect isregistered as an entry in the SDL, and hence the SDL is rewritten. Inthis example, 4 blocks for replacement assignment as in item (5), andonly 3733 defects each with an SLR flag as in item (8) have beenpreviously registered in the SDL. Therefore, the number of residualentries registrable in the SDL, which has a maximum number ofregistrable defects of 3837, is 100. Accordingly, the number of defectsto be registered with the SLR is also restricted to 100 at a maximum.

Depending upon the conditions of use, the following worst case isconceivable. Namely, as a combination of replacement registration andSLR registration, at first, 100 SLR registrations are performed, andthen, the 100 defects registered with SLRs are successively subjected toreplacement assignment. The 100 replacement blocks are deteriorated, orthe like, and an attempt is made to perform reassignment. However, thereplacement blocks have been depleted. Therefore, all are changed intoSLR again.

In this example, the number of the SDL rewrite count is also restrictedto 100×3=300 with respect to the worst case. Therefore, in the medium ofthis example, which is capable of being rewritten 300 times or more,there is no fear that the SDL itself is deteriorated. Accordingly, it ispossible to use the medium of the present invention in a conventionalwrite and read drive or file system with no problem.

Conversely, if the number of replacement blocks and the number ofresidual entries registrable as defects in the SDL are restricted to onethird of the overwrite cyclability of the medium, the SDL update countwill not exceed the overwrite cyclability of the medium.

The PDL will not be rewritten basically unless reformatting isperformed, even if new defect registration or replacement is performed.

Therefore, by using the recording medium satisfying the conditionsdescribed in the foregoing items (1) to (9), it is possible to restrictthe rewrite count of the defect management area so as not to exceed theallowable number of cycles of replacement.

EXAMPLE 2

Now, consideration will be given to the case where the medium of theforegoing example is reformatted by mistake. The reformatting process isof two types: a logical formatting process for restructuring only a filesystem, and a physical formatting process for initializing the SDL fordefect management. First, the former logical formatting process will beconsidered. In the case where logical formatting is performed with aconventional method, with a conventional logical formatter which is aconventional application, most of the file system data is located in thevicinity of the beginning of the user area, i.e., in the vicinity offrom LBA=0 to LBA=512, and the user file is also recorded from thevicinity of LEA=256. However, about 256 blocks in the vicinity of thebeginning of the user area (except for about 7680 sectors registered inthe PDL out of the sectors from the vicinity of PSN=32400h toPSN=35200h) are unrecordable, and hence replacement is performedtherefor, so that respective spare areas are assigned thereto. However,the number of the 256 blocks is larger than 100, which is the number ofthe spare areas. Accordingly, after all, spare area overflow is causedimmediately after use, resulting in a recording error. Consequently, theuser immediately notices that the medium cannot be reformatted and used.Therefore, substantially, the user cannot reformat and use the medium ofthis example.

Now, the case of physical formatting will be considered. If physicalformatting is performed, the information of the SDL is lost, but theP-List in the PDL is stored. Therefore, the sectors ranging from thevicinity of PSN=32400h are used for the spare area, as shown in FIG. 9.If an attempt is made to record the file system after physicalformatting, the recording cannot be performed because, for example, thesector corresponding to LSN256 is in the unrecordable area.Consequently, the replacement as shown in FIG. 7 is to be performed.However, the replacement area is also in the unrecordable area.Accordingly, after several (M) tries, the formatting is abnormallyterminated, i.e., erroneously terminated as shown in the lower rightsection of FIG. 7 after all. Consequently, the user cannotre(physical)-format and use the medium of this example.

The DVD-RAM has a function of SSA expansion/assignment for adding aspare area afterward when the spare area has been depleted. However, inthis example, even if the SSA has been assigned, the portion in thevicinity of the final PSN which is the beginning portion of the SSA tobe used is unrecordable. Therefore, even if an attempt is made to assignthe spare area to the SSA, recording ends in failure. Consequently, itis also impossible to use the SSA.

Alternatively, re(physical)-formatting can also be accomplished bytranslation of the SDL to the PDL. However, in this example, since thePDL has been filled with the P-List from the beginning, after all,reformatting cannot be achieved by this method.

Further, there can be also adopted a method of performing certificationupon formatting. However, the formatting with certification will not beperformed successfully for the medium of this example, in which the PDLhas been filled with the P-List, and the total number of unrecordableareas is larger than the number of SDL registrable entries.

Thus, the user cannot reformat and use the medium with any methods, solong as a conventional formatting application is used. However, it ispossible to perform the erasing operation of a conventional file evenwithout reformatting, and hence there is no inconvenience for use.Therefore, it suffices that it is made known to the user at the point ofsale thereof that the medium of this example is unreformattable, andthere is no particular fear that confusion may be caused. Further, evenin the case where a user may attempt to perform reformatting by use of awrong operation, the user immediately notice it. Therefore, there is norisk that the whole user data is lost due to deterioration of the mediumcaused by continued wrong use.

Of course, not only will the user notice from a package or the like thatthe medium is unusable upon reformatting, but also the medium isdesirably described as such on its labeled side, or the like, of themedium. If possible, another method is desirably adopted in combinationtherewith in which the color of the label or the color of the cartridgeis made different from that of the conventional reformattable medium soas to make it easier to discriminate them.

EXAMPLE 3

An example of a method of forming the unrecordable area will beconsidered. In the DVD-RAM, as shown in FIG. 6, the physical ID (addressinformation) is arranged in the form of an embossed pit at the beginningof each recording sector. For ensuring reliability, the addressinformation for identifying one sector is recorded quadruply.

The write and read drive judges the address to be correct even if onlyone of the quadruple address information is readable. Therefore, all thequadruple address information is set so as not to be normally read inorder to make the sector unrecordable.

As a method of preventing each address from being normally read, the IDcorresponding to an ID error detection code (IED) added to each addressinformation has been set to be mismatched therewith, as shown in FIG. 8.Specifically, the IED obtained by adding one to the proper matched IEDhas been used. Thus, the logical method in which the IED is set to bemismatched can be applied for mastering of the medium. It can beautomatically applied to all of the media simultaneously with substrateformation. Therefore, it can be advantageously carried out without anincrease in cost. In this example, a means for adding one to the IED wasadopted. However, alternatively, a method may be adopted in which 1 byteat the beginning of each ID is replaced by another one after conversioninto a code word (channel bit). Which method can be more easilyperformed depends upon the circuit configuration of the formatter foruse in mastering.

In this example, the first two sectors and the last three sectors in onetrack have been at least set to be readable in stead of setting all theIDs in the unrecordable areas to be unreadable. More specifically, itwas so configured in the inner circumferential portion that the firsttwo sectors have been readable, the subsequent eight sectors unreadable,the subsequent four sectors readable, the subsequent eight sectorsunreadable, and the last three sectors readable. For the application ofthis configuration to the outer circumferential portion, the first twosectors have been set readable, the subsequent ten sectors unreadable,the subsequent five sectors readable, the subsequent ten sectorsunreadable, four sectors readable, ten sectors unreadable, five sectorsreadable, ten sectors unreadable, and the last three sectors readable.Thus, since the addresses of a part of the track are set to be readable,there is no obstruction to access. Further, in this example, since thesectors in the vicinity of the beginning and the end of the track areset to be readable, the ID information of the switching portion betweena land and a groove can be read with reliability. Therefore, thestability of servo control can be ensured. Furthermore, not less thaneight consecutive ID unreadable sectors are arranged. Consequently, theIDs of at least eight sectors in one ECC block (error correction codeblock) are unreadable. Still further, it is so configured that at leastsix consecutive unreadable sectors thereof are arranged. There is alsopresent a system so configured that even if an ID unreadable sectoroccurs during a write operation, the write operation is performed byautomatically interpolating it according to the write and read drive.However, even in such a system having an interpolation function, it ispossible to cause a recording error with reliability by arranging notless than several consecutive ID unreadable sectors. Namely, it ispossible to intentionally form an unrecordable area.

Alternatively, in contrast to this example, there are also other methodsin which the IDs of the whole circumference are set to be unreadable,and totally different addresses are to be read. In either case, the areabecomes inaccessible, or unreadable.

EXAMPLE 43

As a method for making the ID portion unreadable in Example 3, the IDportion was exposed to recording power to generate a phase change mark.As a result, the ID portion varied in signal level so as to beunreadable. This method does not require modification of a stamper for adisk. Accordingly, if disks are found to be low in overwrite cyclabilityafter small-volume sample production or media production, they can bereused as low-priced media in place of being discarded as defectiveproducts, so that effective utilization of resources can be achieved.Further, it is also possible to ship even the disks manufactured under alow-yield adverse production environment as disks of differentperformances according to their qualities by using this method.

For application of this method, it is desirable from the viewpoint ofproduction efficiency to use a device capable of simultaneously formingmarks on the PIDs of a plurality of tracks such as an initializationdevice.

EXAMPLE 5

Instead of making the ID portion unreadable in Example 3, the track atwhich a total of 5-byte data of PS (PreSYNC) and SYO, which aresynchronization signals at the beginning of the sector in the recordingarea, i.e., guide groove, was intermittently formed. For a DVD-RAM, theposition at which a synchronization signal is recorded is the positionabout 60 bytes away from the header portion. Guide grooves for formingthe 20-byte track between the 50th byte and the 70th byte wereintermittently formed in a 5 channel bit period because of theoccurrence of fluctuations in rotation or 8-bite recording positionshift for improving the overwrite cyclability. Consequently, reproducedsignal level fluctuations in the vicinity of the synchronization signalare intensified, and hence it is impossible to detect thesynchronization signal upon reading. As a result, about 100-byte data inthe vicinity of the beginning of the sector becomes unreadable withreliability because the PS and the SYO are absolutely necessary fordetecting the beginning portion of the recording area of the sector. Ifthe 100-byte data at the beginning of each sector becomes unreadable,the recorded data substantially becomes unreadable. With this method,only a 20-byte area per sector, i.e., a little less than 1% area of atrack, is merely set to be different from the normal one. Therefore,there is no danger of adversely affecting a servo operation or access,and hence it is possible to continuously process a large volume ofsectors.

Accordingly, for example, it is also possible to use a burst cuttingmethod in which a part of a recording layer is burnt off by usinga-high-power layer for recording a bar code (BCA) in place of making thetrack intermittent as described above. This method is suitable foreither large-volume production or low-volume production because it canprocess one disk for a short time.

EXAMPLE 6

An example of the application to a 80-mm-dia DVD-RAM is shown in FIG.10. A recording medium thereof has the following configuration:

(1) The recording blocks (8320 sectors in total) of the beginningportion (4096 sectors) of the user area, and the sectors at fromPSN=31380h to PSN=333FFh belonging to the PSA have been set to be anunrecordable area.

(2) The 4096 sectors (256 blocks) at PSN=0E0220h to 0E121Fh at therearmost portion of the user area have been set to be an unrecordablearea.

(3) The foregoing unrecordable areas have been implemented by settingthe ID error detection data (IED) (see FIG. 8) of the ID, which is theaddress data, so as to indicate a mismatch.

(4) The SSA has not been assigned thereto. Therefore, the rearmostportion of the user data area is located at PSN 0E121Fh. (Total numberof user sectors is 714480.)

(5) A total of 4095 sectors of the known defective sectors other thanthose described in the foregoing items (1) and (2) and a part of theunrecordable sectors described in the item (1) have been previouslyregistered as P-List in the PDL. Therefore, the beginning portion of theuser area shifts from the position where PSN=32400h to the side on whichthe PSN is reduced by about 4095 sectors. Namely, the physical user areatop sector (LBA=0) is located in the vicinity of a position wherePSN=31400h.

(6) The last 3334 blocks in the user data area(except for the recordingblock corresponding to LBA=714223) have been previously registered inthe SDL. However, upon registration, an SLR flag has been set to “1”,and a spare sector was not to be assigned thereto.

(7) The recording blocks corresponding to LBA=16, LBA=256, LBA=512, andLBA=final LBA−256=714223 have been previously registered in the SDL, andeach was assigned a spare. In this step, the sectors at from PSN=31320hto PSN=3234Fh have been utilized for replacement.

(8) Logical formatting has been previously performed with a UDF filesystem. In this step, the 8448 sectors (2100h) at the beginning of theuser data area and the 53344 sectors (3334 blocks) at the rearmostportions thereof were not to be used.

(9) The overwrite cyclability of the medium (recording layer) has beenset to be not less than 600 times.

Below, the principle of operation of this example will be described. Inthis example, the unrecordable area is also present similarly inExample 1. However, since the unrecordable area is not present in alogical user area (logical volume space), which is the user recordingarea after logical formatting, there is no problem for common use. Forthe UDF format, the layout positions of only a Volume RecognitionSequence (VRS) and an AVDP (Anchor Volume Descriptor Pointer) aredetermined, and the VRS is to be recorded at LEA=16, and AVDPs are to berecorded at two or more positions out of the positions where LBA=256,LBA=512, and LBA=N−256 (where N is the final LBA). For the 80-mm-diaDVD-RAM, which is the case of this example, the AVDPs are recorded attwo positions where LBA=256 and LBA=714223. In the AVDP, the layoutpositions of two main and spare volume descriptor sequences (VDSs) arerecorded. In this example, the VRSs have been located at 16 sectorsbeginning at LBA=8488, and 16 sectors beginning at LBA=8448+16. In thesubsequent sectors, an LVID (logical volume integrity descriptor) hasbeen located, and the logical volume space has been located so as tobegin at LBA=8704, and end at LBA=661135. Namely, the user capacityafter logical formatting (logical volume space) is about 1.33 GB. In thelogical volume space, a space bit map, a file set descriptor, adirectory, a user file, and the like are located.

In this example, the sectors where LBA=256 and LBA=714223 for describingthe AVDPs, and the sector where LBA=16 for the VRS are basically locatedin the unrecordable area. However, the LBAs have previously beenassigned for replacement to the area outside the unrecordable area inthe PSA. Therefore, actually, they are recorded in the assignedreplacement recording block (PSN=31320 to 3135Fh). Other file systemdata are all assigned to the area which is not unrecordable in the userarea.

If another defective sector occurs due to deterioration caused byrewriting, adhesion of contaminants, or the like during use of themedium, the sectors at from PSN=3131Fh to PSN=31000h are successivelyassigned thereto as replacement areas. In this example, the sector atPSN=31320h has previously been assigned and registered as a replacementsector. Therefore, the area between PSN=31360h and PSN=32400h in the PSAis regarded as a used spare area, and hence the sectors are not to beassigned as replacement sectors. For this reason, the defect managementcan be performed with respect to a newly occurred defect with noproblem. In this example, only the 50 blocks (320 sectors) at fromPSN=3131Fh to 31000h are used as a spare area. The spare area is presentonly for 50 blocks. Therefore, the replacement assignment count is 50 atmaximum. Namely, the SDL rewrite count associated with replacementassignment is also restricted to 50.

In the DVD-RAM, there is provided a function of performing onlyregistration of a defect, but not performing replacement assignment,other than the replacement assignment. In this case, the defect is to beregistered in the SDL in the same manner as with the replacement.However, the replacement assignment is not performed, and the flag SLRis set to “1”, thereby indicating that the replacement assignment hasnot been performed (see FIG. 11 (b)). Even in this case, the defect isregistered as an entry in the SDL, and hence the SDL is rewritten. Inthis example, four blocks for replacement assignment as in the item (5)and only 3333 defects each with an SLR flag as in the item (8) havepreviously been registered in the SDL. Therefore, the number of residualentries registrable in the SDL which has a maximum number of defectsregistrable of 3837 is 500. Accordingly, the number of defects to beregistered with SLR is also restricted to 500 at a maximum.

Depending upon conditions of use, the following worst case isconceivable. Namely, as a combination of replacement registration andSLR registration, at first, 500 SLR registrations are performed, andthen, the 50 defects out of the defects registered with SLRs aresuccessively subjected to replacement assignment. The 50 replacementblocks are deteriorated, or the like, and an attempt is made to performreassignment. However, the replacement blocks have been depleted.Therefore, all are changed into SLR again.

In this example, the SDL rewrite count is also restricted to500+50+50=600 even with respect to the worst case. Therefore, in themedium of this example, which is capable of being rewritten 600 times ormore, there is no fear that the SDL itself is deteriorated. Accordingly,it is possible to use the medium of the present invention in aconventional write and read drive, or a file system, with no problem.

Conversely, if the sum of twice the number of replacement blocks and thenumber of residual entries registrable as defects in the SDL isrestricted to not more than the overwrite cyclability of the medium, theSDL update count will not exceed the overwrite cyclability of themedium.

The PDL will not be rewritten basically unless reformatting isperformed, even if new defect registration or replacement is performed.

Therefore, by using the recording medium satisfying the conditionsdescribed in the foregoing items (1) to (9), it is possible to restrictthe defect management area rewrite count so as not to exceed theallowable number of cycles of replacement.

EXAMPLE 7

In this example, unrecordable areas were arranged to be dispersedthroughout the user area, and the information of the existing positionthereof was recorded as disk manufacturer's information on a disk asread-only data. In this example, an example of a special-purpose devicedriver is shown. The special-purpose device driver has functions ofreading the existing position data of the unrecordable areas from thedata on the medium, and then registering the data as an invisible fileso that the unrecordable area may not encroach on the user area, andperforming address translation to perform read and write operations.Further, simultaneously, by reading the information on the overwritecyclability of the medium from the data on the medium, it is possible torestrict reformatting or restrict the recording method according to theoverwrite cyclability of the medium. The recording method can berestricted in the following manner. For example, random recording is notperformed, and the recording method is restricted to sequentialrecording as with a CD-R, and, as a result, it is possible to remarkablyreduce the overwrite cyclability of the medium.

This example is characterized by the following fact. Namely,unrecordable (write restricted) areas are present in various portions inthe user area. By utilizing this configuration, it is set that read andwrite operations cannot be performed in a conventional device driver, sothat it becomes necessary to perform read and write operations with onlyspecial-purpose software. By utilizing this fact, it becomes possible toconstruct, for example, the special-purpose system as shown in the upperright section of FIG. 1. With the special-purpose system, it becomespossible to use only a file system based on sequential recording so thatthe rewrite count of a part of the medium may not be increasedextremely.

EXAMPLE 8

The concept of an optical recording system of the present invention willbe described by reference to FIG. 1.

As for a conventional medium, it can be written, and read by usingstandard control software (ex., a device driver included with OS) with astandard read and write drive. On the other hand, for a low-pricedmedium that has a restriction on its overwrite cyclability, as inExamples 1 to 6, a specific area on the medium is made unrecordable, andthe medium is previously subjected to specific logical formatting to beshipped. Consequently, it is possible to restrict the operation ofstandard control software. Under such circumstances, even in case a userattempts to reformat and use the medium, the user cannot substantiallyuse it because of the unrecordable area. Therefore, it is possible toeliminate the risk that the low-priced medium having a restriction onits overwrite cyclability will be used with the user's own format ordriver, and, as a result, the user data is corrupted or lost.

Of course, if a standard drive is used in combination with suchspecial-purpose control software, as in Example 4, it is also possiblethat the user will reformat and use the medium, and it is possible tosufficiently ensure the substantial rewrite count the user bodily sensesby cache management or the like.

In any case, the present invention is characterized in that a mediumwith a write and read function is so configured as to be written andread with a conventional drive (standard drive) with security.

By using the present invention as described above, it is possible toeasily implement the extension of a write protection function, or thelike, without changing hardware or physical specifications. In addition,it is possible to provide a secure optical recording system having nodanger of being wrongly written or causing data corruption with aconventional drive which does not recognize the presence of theextension.

The effect of the present invention is not limited to the foregoingexamples in this regard, the unrecordable area formation methoddescribed in Example 2 is not limited to IED mismatching. For example, apit or the like may be provided in a part of a recording track.Alternatively, the recording layer may be formed by being modified by anintense laser light, or the like. In Examples 1 and 3, the number ofusable blocks in the PSA is set to be 253, but this number may be variedaccording to the overwrite cyclability of the medium. For example, if amedium having an overwrite cyclability of 100 times is used, the initialregistration for the SDL may be performed so that the number of usableblocks in the PSA is 100 or less. With the method of this example, forexample, it is difficult to suppress the deterioration of a trial writearea. Therefore, if possible, desirably, the rewrite count of about 1000times is ensured, and the number of usable blocks in the PSA is also setto be about 1000. In such a case, the arrangement of the disabled areas,or the like, of the medium may be changed from the one described above,or may not be changed. Although an example was described in which theUDF for random recording was used as a file system (logical format), itis also possible to use a file system for write-once recording or forsequential recording. In such a case, for example, it is recommendableto use a cipher so as to allow the operation with only a specific devicedriver, as in Example 4. Further, in the foregoing examples, adescription was given of a DVD-RAM as a conventional optical disk.However, the technology described above is basically applicable to allrewritable media.

According to the present invention, an information recording andreproducing system, comprising: an information recording medium having awrite and read restriction comprising at least two or more independentlywritable and readable user recording blocks, out of the user recordingblocks, at least one or more blocks being an unrecordable, unreadable,or inaccessible restricted block; and a computer system or a write andread drive having a processing function for performing read and writecontrol such that an area except for the restricted blocks is asubstantial user area, the information recording medium being used inthe computer system or the write and read drive.

According to a feature of the information recording and reproducingsystem as described above, the restricted blocks are substantiallyexcluded from the user area by registering the restricted blocks asdefects.

According to another feature of the information recording andreproducing system as described above, the restricted blocks aresubstantially excluded from the user area by registering the restrictedblocks as invisible files.

In accordance with the present invention, an information recording andreproducing system includes an information recording medium having awrite and read restriction comprising at least two or more independentlywritable and readable user recording blocks, out of the user recordingblocks, at least one or more blocks being unrecordable, unreadable, orinaccessible restricted blocks; and a means having a processing functionfor reading encoded data or encrypted data stored on the recordingmedium, and decoding or decrypting the read data to obtain the layoutinformation of the restricted blocks, and performing at least one ofwrite and read control or logical format such that all the restrictedblocks are not substantially user areas based on the restricted blocklayout information obtained by using the information recording medium.

Further, the present invention is directed to an information recordingmedium which includes at least a plurality of independently writable andreadable user recording blocks; spare blocks each for replacing a userrecording block having a defect; and at least a defect management tablerecording area for recording the relationship between the defectiveblocks and the spare blocks, wherein the number of the spare blocks isset to be smaller than the overwrite cyclability of the recordingmedium.

The present invention is also directed to an information recordingmedium, which includes at least a plurality of independently writableand readable user recording blocks; spare blocks each for replacing auser recording block having a defect; and at least a defect managementtable recording area for recording the relationship between thedefective blocks and the spare blocks, wherein a plurality of thedefective blocks and the spare blocks are previously recorded in thedefect management table, and the number of residual blocks registrablein the defect management table are set to be smaller than the overwritecyclability of the recording medium.

According to a feature of the information recording medium as describedabove, the sum of the number of the spare blocks and the number ofresidual blocks registrable in the defect management table is set to besmaller than the overwrite cyclability of the recording medium.

According to another feature of the information recording medium asdescribed above, the number of the spare blocks and the number ofresidual blocks registrable in the defect management table arerespectively set to be smaller than one third of the overwritecyclability of the recording medium.

The foregoing invention has been described in terms of Preferredembodiments. However, those skilled in the art will recognize that manyvariations of such embodiments exist. Such variations are intended to bewithin the scope of the present invention and the appended claims.

What is claimed is:
 1. An information recording medium, comprising: atleast two blocks of independently writable user recording blocks, and atleast one block of the user recording blocks being an unrecordablerestricted block; ones of the recording blocks having physical addressdata arranged thereon, the physical address data being made up of a codeindicative of an address number and an address error detection code forverifying the correctness of the address number, wherein the codeindicative of the address number is mismatched with the address errordetection code for verifying the correctness of the address number inthe restricted block.
 2. The information recording medium according toAn information recording medium, comprising: at least two blocks ofindependently writable user recording blocks, and at least one block ofthe user recording blocks being an unrecordable restricted block; onesof the recording blocks having physical address data arranged thereon,the physical address data being made up of a code indicative of anaddress number and an address error detection code for verifying thecorrectness of the address number, wherein the address number indicatedby the physical address data is different from the address number of therestricted block in the restricted block.
 3. An information recordingmedium, comprising: at least two blocks of independently writable userrecording blocks, and at least one block of the user recording blocksbeing an unrecordable restricted block; wherein the user recording blockis an error correction code block including a plurality of user sectors,wherein the user sectors individually have independent address numbers,and all the user recording blocks to which the user sectors having thesmallest 257 numbers of the address numbers belong are at leastunrecordable, restricted blocks.
 4. The information recording mediumaccording to claim 3, wherein the user sectors individually haveindependent address numbers, and all the user recording blocks to whichthe user sectors having the smallest 513 numbers of the address numbersbelong are at least unrecordable, restricted blocks.
 5. The informationrecording medium according to claim 3, wherein all the user recordingblocks to which the user sectors having the largest 257 numbers of theaddress numbers belong are at least unrecordable restricted blocks. 6.An information recording medium, comprising: at least two blocks ofindependently writable user recording blocks, and at least one block ofthe user recording blocks being an unrecordable restricted block;wherein a total number of the restricted blocks on the informationrecording medium is set to be larger than a total number of therecording blocks registrable in a defect management table.
 7. Theinformation recording medium according to claim 1, wherein theinformation recording medium is at least one of: an optical recordingmedium, a CD (compact disk) optical recording medium, CD-ROM (read onlymemory) optical recording medium, a DVD (digital versatile disk) opticalrecording medium, a DVD-RAM (random access memory) optical recordingmedium, a DVD-ROM optical recording medium, a MO (magneto-optic) opticalrecording medium, a WORM (write once, read many) optical recordingmedium, a MO-WORM optical recording medium, and a CCW (continuouscomposite write) optical recording medium.
 8. The information recordingmedium according to claim 2, wherein the information recording medium isat least one of: an optical recording medium, a CD (compact disk)optical recording medium, CD-ROM (read only memory) optical recordingmedium, a DVD (digital versatile disk) optical recording medium, aDVD-RAM (random access memory) optical recording medium, a DVD-ROMoptical recording medium, a MO (magneto-optic) optical recording medium,a WORM (write once, read many) optical recording medium, a MO-WORMoptical recording medium, and a CCW (continuous composite write) opticalrecording medium.
 9. The information recording medium according to claim3, wherein the information recording medium is at least one of: anoptical recording medium, a CD (compact disk) optical recording medium,CD-ROM (read only memory) optical recording medium, a DVD (digitalversatile disk) optical recording medium, a DVD-RAM (random accessmemory) optical recording medium, a DVD-ROM optical recording medium, aMO (magneto-optic) optical recording medium, a WORM (write once, readmany) optical recording medium, a MO-WORM optical recording medium, anda CCW (continuous composite write) optical recording medium.
 10. Theinformation recording medium according to claim 6, wherein theinformation recording medium is at least one of: an optical recordingmedium, a CD (compact disk) optical recording medium, CD-ROM (read onlymemory) optical recording medium, a DVD (digital versatile disk) opticalrecording medium, a DVD-RAM (random access memory) optical recordingmedium, a DVD-ROM optical recording medium, a MO (magneto-optic) opticalrecording medium, a WORM (write once, read many) optical recordingmedium, a MO-WORM optical recording medium, and a CCW (continuouscomposite write) optical recording medium.
 11. A system comprising: aninformation recording medium drive having mechanical components to atleast one of: produce, read and write an information recording mediumhaving at least one restricted block; and at least one informationrecording medium including: at least two blocks of independentlywritable user recording blocks, and at least one block of the userrecording blocks being an unrecordable restricted block; ones of therecording blocks having physical address data arranged thereon, thephysical address data being made up of a code indicative of an addressnumber and an address error detection code for verifying the correctnessof the address number, wherein the code indicative of the address numberis mismatched with the address error detection code for verifying thecorrectness of the address number in the restricted block.
 12. Thesystem according to claim 11, wherein the information recording mediumis at least one of: an optical recording medium, a CD (compact disk)optical recording medium, CD-ROM (read only memory) optical recordingmedium, a DVD (digital versatile disk) optical recording medium, aDVD-RAM (random access memory) optical recording medium, a DVD-ROMoptical recording medium, a MO (magneto-optic) optical recording medium,a WORM (write once, read many) optical recording medium, a MO-WORMoptical recording medium, and a CCW (continuous composite write) opticalrecording medium.
 13. A system comprising: an information recordingmedium drive having mechanical components to at least one of: produce,read and write an information recording medium having at least onerestricted block; and at least one information recording mediumincluding: at least two blocks of independently writable user recordingblocks, and at least one block of the user recording blocks being anunrecordable restricted block; ones of the recording blocks havingphysical address data arranged thereon, the physical address data beingmade up of a code indicative of an address number and an address errordetection code for verifying the correctness of the address number,wherein the address number indicated by the physical address data isdifferent from the address number of the restricted block in therestricted block.
 14. The system according to claim 13, wherein theinformation recording medium is at least one of: an optical recordingmedium, a CD (compact disk) optical recording medium, CD-ROM (read onlymemory) optical recording medium, a DVD (digital versatile disk) opticalrecording medium, a DVD-RAM (random access memory) optical recordingmedium, a DVD-ROM optical recording medium, a MO (magneto-optic) opticalrecording medium, a WORM (write once, read many) optical recordingmedium, a MO-WORM optical recording medium, and a CCW (continuouscomposite write) optical recording medium.
 15. A system comprising: aninformation recording medium drive having mechanical components to atleast one of: produce, read and write an information recording mediumhaving at least one restricted block; and at least one informationrecording medium including: at least two blocks of independentlywritable user recording blocks, and at least one block of the userrecording blocks being an unrecordable restricted block; wherein theuser recording block is an error correction code block including aplurality of user sectors, wherein the user sectors individually haveindependent address numbers, and all the user recording blocks to whichthe user sectors having the smallest 257 numbers of the address numbersbelong are at least unrecordable restricted blocks.
 16. The systemaccording to claim 15, wherein the user sectors individually haveindependent address numbers, and all the user recording blocks to whichthe user sectors having the smallest 513 numbers of the address numbersbelong are at least unrecordable restricted blocks.
 17. The systemaccording to claim 15, wherein all the user recording blocks to whichthe user sectors having the largest 257 numbers of the address numbersbelong are at least unrecordable restricted blocks.
 18. The systemaccording to claim 15, wherein the information recording medium is atleast one of: an optical recording medium, a CD (compact disk) opticalrecording medium, CD-ROM (read only memory) optical recording medium, aDVD (digital versatile disk) optical recording medium, a DVD-RAM (randomaccess memory) optical recording medium, a DVD-ROM optical recordingmedium, a MO (magneto-optic) optical recording medium, a WORM (writeonce, read many) optical recording medium, a MO-WORM optical recordingmedium, and a CCW (continuous composite write) optical recording medium.19. A system comprising: an information recording medium drive havingmechanical components to at least one of: produce, read and write aninformation recording medium having at least one restricted block; andat least one information recording medium including: at least two blocksof independently writable user recording blocks, and at least one blockof the user recording blocks being an unrecordable restricted block;wherein a total number of the restricted blocks on the informationrecording medium is set to be larger than a total number of therecording blocks registrable in a defect management table.
 20. Thesystem according to claim 19, wherein the information recording mediumis at least one of: an optical recording medium, a CD (compact disk)optical recording medium, CD-ROM (read only memory) optical recordingmedium, a DVD (digital versatile disk) optical recording medium, aDVD-RAM (random access memory) optical recording medium, a DVD-ROMoptical recording medium, a MO (magneto-optic) optical recording medium,a WORM (write once, read many) optical recording medium, a MO-WORMoptical recording medium, and a CCW (continuous composite write) opticalrecording medium.